This paper examines the micro-foundations of the second-order elections model of European Parliament (EP) elections. We extend the existing literature in several ways. First, we propose an individual-level model of voting behaviour in second-order elections. Second, we present the first study using experimental methods to test the predictions of the second-order model, allowing us to test the individual-level propositions about vote choice in a controlled environment. Importantly, we also examine the conditioning effect of information on the ‘second-order’ nature of voting behaviour in EP elections. Our findings show that while voters base their EP vote choices primarily on domestic preferences, those who are given additional information about the European integration dimension are also more likely to vote on this basis.